Adjustable-rate Mortgages

An adjustable-rate mortgage (ARM) has an interest rate that changes -- usually once a year -- according to changing market conditions. A changing interest rate affects the size of your monthly mortgage payment. ARMs are attractive to borrowers because the initial rate for most is significantly lower than a conventional 30-year fixed-rate mortgage. Even in 2010, with interest rates on the 30-year fixed mortgage at historic lows, the ARM rate is almost a full percentage point lower [source: Haviv]. ARMs also make sense to borrowers who believe they'll be selling their home within a few years.

If you're considering an ARM, one important thing to remember is that intentions don't always equal reality. Many ARM borrowers who intended to sell their homes quickly during the real estate boom were instead stuck with a "reset" mortgage they couldn't afford. Many of them never fully understood the terms of their ARM agreement. Here are the key numbers to look for:

  • How often your interest rate adjusts -- A conventional ARM adjusts every year, but there are also six-month ARMs, one-year ARMs, two-year ARMs and so on. A popular "hybrid" ARM is the 5/1 year ARM, which carries a fixed rate for five years, then adjusts annually for the life of the loan. A 3/3 year ARM has a fixed rate for the first three years, then adjusts every three years.
  • There will also be caps, or limits, to how high your interest rate can go over the life of the loan and how much it may change with each adjustment. Interim or periodic caps dictate how much the interest rate may rise with each adjustment and lifetime caps specify how high the rate can go over the life of the loan. Never sign up for an ARM without any caps!
  • The interest rates for ARMs can be tied to one-year U.S. Treasury bills, certificates of deposit (CDs), the London Inter-Bank Offer Rate (LIBOR) or other indexes. When mortgage lenders come up with their ARM rates, they look at the index and add a margin of two to four percentage points. Being tied to these index rates means that when those rates go up, your interest goes up with it. The catch? If interest rates go down, the rate on your ARMs may not [source: Federal Reserve]. In other words, read the fine print.

Now let's look at some of the less common mortgage options, like government-sponsored loans, balloon mortgages and reverse mortgages.